WATER QUALITY INDICATORS OF OREGON HOLLOW, A HEADWATER TRIBUTARY; PIKE RUN WATERSHED, WASHINGTON COUNTY, PENNSYLVANIA

Pike Run Watershed, located in southwestern Pennsylvania, is a thirty square mile area draining into the Monongahela River in the eastern portion of Washington County. The area was extensively mined throughout the 1900's for coal and is now explored and drilled for natural gas. Along with the extraction of these resources and continued development, the region’s waterways are vulnerable to legacy mine, agricultural, and road pollution. These sources could have a significant effect on the ecology of the Pike Run Watershed including local trout populations, which are a primary target of recreational fishermen in nearby communities. Oregon Hollow, a 2.7 mile long first-order tributary that enters Gorby Run before it ultimately feeds Pike Run, is of particular interest with respect to contamination as it is bordered by both abandoned coal mines and Interstate 43. The purpose of this study was to determine the health of the watershed by measuring water quality indicators such as: conductivity, chloride concentration, temperature, and pH. The lower 1.5 miles of Oregon Hollow were found to have conductivity and chloride concentrations of 1100 μS/cm and 300 mg/L, respectively, with values decreasing downstream. These values indicate negative impacts from anthropogenic sources when compared to the PA Department of Environmental Protection standards of 150-500 μS/cm and 250 mg/L, as well as to other tributaries in the watershed and the main stem of Pike Run. In the headlands of the tributary, a small wetland is situated among seeps, mine-slag fill and below a road salt repository. Conductivity measurements in the wetland were as high as 2800 μS/cm. Future study seeks to further identify the sources of contamination, particularly in the wetland, through construction of a well nest, mapping of seeps, and characterization of ground water and surface water flow through the system, wetland and the stream.